PULMONARY CHANGES AFTER EXPOSURE TO VERMICULITE CONTAMINATED WITH FIBROUS TREMOLITE

Publisher Website
Google Scholar
Abstract
Workers exposed to vermiculite contaminated with fibrous tremolite were surveyed for the presence of respiratory symptoms by questionnaire, and for pneumoconiosis by chest radiograph. Pulmonary function was measured by spirometry and single-breath CO diffusing capacity (DLCOsb). Fiber exposure indexes, expressed as fiber/milliliter-year, were derived for each worker from available industrial hygiene data and work histories. The estimated cumulative exposure for the work force ranged from 0.01-39 fiber/milliliter-year. Discriminant analysis demonstrated significant correlates with shortness of breath and pleuritic chest pain to cumulative fiber exposure. The radiographic changes were limited to pleural changes and involved 4.4% of the population. Parametric and discriminant analysis demonstrated a significant correlation with radiographic changes and cumulative fiber exposure. There were no correlations between spirometry of DLcosb and fiber exposure. Exposure to vermiculite contaminated with fibrous tremolite casued pleural changes in occupationally exposed workers. This was supported by the previously identified 12 cases of benign pleural effusions in this working population and the association of pleural radiographic changes and pleuritic chest symptoms with cumulative fiber exposure. The lack of significant parenchymal radiographic, spirometric and DLCOsb changes most likely reflected the low cumulative fiber exposure.